In manufacturing process of liquid crystal display panels, testing for line defect of display panel is an indispensable processing step for ensuring display quality.
With more and more minimized products emerging and much higher precision of display panels, conventional test methods cannot meet the requirements on line defect inspection of display panels. Due to this demand, a test method of graph generator shorting has been proposed for line defect in a display panel by testing the graphic display of the display panel by inputting control signals into the display panel. Due to limitations of the test method of graph generator shorting, many line defects cannot be found, and a true line defect cannot be distinguished from a false line defect.
The test procedure of graph generator shorting test method is illustrated in FIG. 1, and FIG. 2 illustrates the display result of a display panel during the module signal inputting state. As can be seen from the comparison between FIGS. 1 and 2, the line-defect indicating line 1 in FIG. 1 disappears in FIG. 2, while the line-defect indicating lines 2 and 3 in FIG. 1 remain in FIG. 2, therefore the indicating line 1 in FIG. 1 indicates a false defect, and the indicating lines 2 and 3 indicate true defects. The reason why the true defect indicating lines 2 and 3 appear may involve broken wires in the display panel. The indicating line 1 occurs because: during the testing procedure of the graph generator shorting test method, the presence of static electricity (ESD) makes wires corresponding to the indicating line 1 become conductive, thereby giving rise to the line defects in the form as illustrated in FIG. 1. However, application of the traditional graph generator shorting test method is impossible to distinguish between the above-mentioned false and true defects.